The following paragraphs are not an admission that anything discussed in them is prior art or part of the knowledge of persons skilled in the art.
Many lift trucks, particularly those for use indoors, e.g., in warehouses and the like, have been powered electrically, to avoid the issue of discharge and accumulation of fumes from an internal combustion engine. For this purpose, they are often provided with large battery packs of lead acid batteries.
These battery packs may be large and cumbersome. For a lift truck operated continuously, e.g., operated by running three eight hour shifts a day, it may be necessary to provide up to three full battery packs, one of which is in use at any one time, one of which is being charged, the other of which is left to cool after being charged, for example. Additionally, resources may be required for maintaining a charging station, including necessary equipment, personnel to operate it, etc.
Thus, while the cost of an individual battery pack for a lift truck may be reasonable, the overall costs with maintaining the necessary battery packs to operate a lift truck can be substantial.
It is therefore desirable, for at least some applications, to consider alternative power sources for an electric lift truck, and for other electric vehicles and the like, which do not require the cost and complexity of charging large battery packs.
It is has been proposed to use a fuel cell stack as a power source instead of a battery pack. A fuel cell stack, incorporated into a complete fuel cell power pack or module (FCPP), has a number of advantages. A fuel cell stack can run continuously, provided it is supplied with fuel. To recharge a FCPP, it is necessary only to recharge a fuel storage device, e.g., a hydrogen storage cylinder, forming part of the FCPP. Commonly, the oxidant necessary as the other reactant for the fuel cell is drawn from the air. A hydrogen cylinder or other fuel storage device can be recharged quickly and simply, and does not require a cool down period or anything similar.
Thus, a single FCPP can be used to replace the battery pack of an electric lift truck, and further applications.